PTO Units PTO Unit Informational Documents F1C (1231) – 300 Series Side Load PTO Part Drawing F1B (1241) – 400 Series Side Load PTO Part Drawing Clutch Operation and Adjustment P-1926: Operations and Parts Manual – #3 SAE Housing / 11.5″ SAE Flywheel P-1943-E: Operations and Parts Manual – #3 SAE Housing / Flat Face Flywheel P-1934: Operations and Parts Manual – #4 SAE Housing / Machined Flywheel P-1231-D: Operations and Parts Manual – Duetz 1011-F